A plan to build 498 town houses that would swell the 3,300-population of the Prince William County town of Dumfries by 25 percent has generated wide opposition, and last night the Town Council balked at granting the needed rezoning.

The council voted to give Wilbur H. Ausley, the local developer who has proposed building the town houses, 30 days to come up with a compromise proposal. His development would go on the town's last remaining vacant land: 83 acres on a hill overlooking I-95, Route 1 and the Potomac River.

The town house development, to be called Battery Hill after Civil War and Revolutionary War forts thought to have stood on the hill, has become the focus of controversy because much of the crime in the town occurs in town house projects that already exist there, according to town officials.

Ausley offered last night to build town houses on only half of his property and place the main entrance to the project close to the I-95 exit. The original entrance was to have been primarily on Route 1 in downtown Dumfries, which consists of several dozen stores and houses.

Ausley's last-minute concessions appeared to have staved off almost certain defeat for the town house project. Last week the planning commission voted against it unanimously, urged by an angry audience of residents who had voted 52 to 1 against the project at the planning commission's public hearing.

Dumfries Mayor Olney (Butch) Brawner accused Ausley of threatening the town by telling the planning commission that he would erect "crackerboxes" if the rezoning was denied. Ausley insisted that while he never used the word crackerboxes, he would put up low-priced modular homes in the $60,000 range rather than $75,000 to $90,000 town houses that could be "the nicest town homes in Eastern Prince William County."

Ausley said that his project would include a swimming pool, tennis courts, 30 acres of open space, five acres of park donated to the town and a five-acre recreation area for residents.

He said that his town houses probably would be among the nicest residences in the town, which has, in addition to three low-priced town house complexes, several subdivisions of mobile homes. The town now has 921 single-family homes and 1,013 town houses.

Few of the town's historic buildings survive, although Dumfries recently had a historic marker placed on I-95 inviting motorists to visit the restored Weems-Botts museum, purchased as a book store in 1798 by Parson Mason Locke Weems, a bookseller whose early "Life of Washington" included the famous--and fictitious--cherry tree story.